25 lines
771 B
Go
25 lines
771 B
Go
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package sun
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import (
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"time"
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"b612.me/astro/basic"
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)
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// ParallacticAngle 太阳视差角（天顶方向角） / solar parallactic angle.
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//
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// lon/lat 为观测者经纬度，东正西负、北正南负；返回值为有符号视差角，单位度。
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func ParallacticAngle(date time.Time, lon, lat float64) float64 {
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return basic.ParallacticAngleByHourAngle(HourAngle(date, lon, lat), ApparentDec(date), lat)
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}
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// ParallacticAngleN 截断项太阳视差角（天顶方向角） / truncated solar parallactic angle.
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func ParallacticAngleN(date time.Time, lon, lat float64, n int) float64 {
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jde := basic.Date2JDE(date.UTC())
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return basic.ParallacticAngleByHourAngle(
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HourAngleN(date, lon, lat, n),
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basic.HSunApparentDecN(basic.TD2UT(jde, true), n),
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lat,
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)
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}
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